中文摘要：

研究时效成形过程蠕变与应力松弛行为的关联规律及其转换模型。通过分析金属材料蠕变与应力松弛行为的产生机理及其相互关系,分别建立基于加工硬化假说和时效假说的蠕变-应力松弛基本转换模型。在此基础上,针对蠕变/应力松弛时效成形过程将蠕变与时效同步进行的特征,进一步建立基于蠕变公式的时效应力松弛行为预测模型。以铝合金7055T6为试验材料,在120℃时效温度下分别进行不同应力水平下的蠕变与应力松弛试验,利用SPSS和Origin软件,开展蠕变本构方程中的材料常数拟合分析,并引入时效应力松弛预测模型,实现对应力松弛行为的预测。经不同应力水平下的预测结果与试验结果对比分析表明,该模型能较好地实现对时效成形过程中的应力松弛行为预测。

英文摘要：

The relationship and the conversion model between creep and stress relaxation for age forming process are studied. Through analyzing the mechanism of creep and stress relaxation behaviors of metal materials and the relationship between them, two types of conversion models from creep data to stress relaxation behavior based on work hardening hypothesis and aging hypothesis are established respectively. Then according to the feature that creep and aging coexist synchronously in the process of creep/stress-relaxation age forming, a set of prediction model for aging stress-relaxation behavior is established based on aging creep equations. In order to verify the theoretical model, creep and stress-relaxation experiments at the aging temperature of 120 ~C and different stress levels on aluminum alloy 7055T6 are carried out separately. Using the software of Origin and SPSS, material constants in the creep constitutive equations are achieved by regressive analysis. Then the established aging stress-relaxation prediction model based on creep equations is introduced to predict stress-relaxation behaviors. Comparisons between experiment results and prediction ones at different initial stress levels show that the established model can be used to predict stress-relaxation behaviors in the process of creep age forming.